DESCRIPTION: This new grant application includes undergraduate students in the investigation of the involvement of actin filaments in an important, though unique, fertilization event in ascidians. That event is the mitochondrial translocation occurring from head to tail during sperm activation that provides the force for penetration of part of the ascidian egg vitelline coat. The proposal includes the use of digital video microscopy, electron microscopy, Western blotting, immunofluorescence, microsequencing, protein purification methods, monoclonal antibody production, cell permeabilization and actin probes. The specific aims are: 1) to study the regulation and process of actin polymerization as it relates to mitochondrial translocation; 2) to study the structural nature of the actin filaments and their attachments to the mitochondrion and the plasma membrane.